This invention relates to a process for increasing the pulse repetition frequency in a laser, more particularly a CO.sub.2 laser used for inscribing of ceramic substrates for hybrid modules.
As is well known, a gas type of laser system substantially comprises discharge tubes, a high voltage supply unit, a pulse generator for discharge control of the tubes and a control unit or panel. A piece to be scribed, such as ceramic substrate, is positioned on a table X-Y which is powered and operated by a numerical control according to a preselected program. The table displacement rate and repetition frequency of laser pulses are selected to provide 4-5 pulses for each millimeter of displacement of the ceramic substrate. For example, the repetition frequency will be 50 Hz when the table rate or speed is 10 mm/sec; the frequency will be 500 Hz when the table rates is 100 mm/sec; the repetition frequency will be 1000 Hz when the table rate is 200 mm/sec. However, it is well known that at such a frequency, the energy in the pulse rapidly decays and is no longer sufficient for enscribing. Using the prior art devices it is impossible to attain certain rates of enscribing speeds even if the power of the laser is increased. This results from the fact that recharging time of the gas mixture in the tube is insufficient, if the pulse frequency for the discharge control exceeds a predetermined limit.